Improvement in machines for drawing bolts and spikes



UNITED STATES PATENT OFFICE.

JOHN C. CHAPMAN, OF CHARLESTOWN, MASSAOHULETTS.

IMPROVEMENT IN MACHINES FOR DRAWING BOLTS AND SPIKES.

Specication forming part of Letters Patent No. 37,332, dated January 6, 1863.

State of Massachusetts, have invented an Improved Machine for Drawing Bolts and Spikes from Timbers, &c., of which the following is a full, clear, and exact description, reference being had to the accompanying drawing', making part of this specification, in which is represented acentral longitudinal section through my improved machine.

`My invention has for its object to remove bolts or spikes from timbers or sides of ships, 86e., while undergoing repairs more economically and expeditiously than is accomplished by the machines for that purpose now in use, and, as it is desirable to use the withdrawn bolt again, I construct my machine so that it may'be drawn without injury or bending.

My said invention consists of a pair of levers linked together, the upper ends of which slide in inclined grooves in the foot of a screwshaft, their lower ends forming jaws or nippers, which grip and draw the bolt outward as the shaft ascends. y

To enable others skilled in the art to understand my invention, I will proceed to describe the manner in which I have carried it out.

In the drawing, A is a metal frame, of sufficient strength to bear the required strain, the lower part of which rests upon the face of the timber from which the bolt is to be drawn. Through ahole in the top of this frame passes the shaft B, having a screw-thread cut upon its entire length, and on which works@ nut,

G, turned by handles a, thus raising or lower ing the shaft B. This shaft is made hollow for the purpose of receiving the end of a bolt, which might project some distance from the face of the timber. The lower end of the shaft B terminates in a circular footpiece, D,

in the periphery of which and diametrically opposite to each other are cut two inclined grooves, b b. Within these grooves slide the upper ends of two levers, E E, pivoted or shackled to the links o. Thelower ends of these levers (which are of hardened steel) form jaws or nippers, which are provided with asperities on their inner surfaces,so as to clutch -lirmly the bolt to be drawn. The backs of these levers slide in slotted guides d d in the uprights of the frame A A, and are thus kept in a position for insuring a proper hold of the bolt.

The operation of drawing the boltis as follows, viz: The machine is placed over the bolt t0 be drawn. The part of the bolt projecting above the timber is embraced by the jaws, and the operator, turning the handles a a of the nut G, raises the shaft B and footpiece D. As the foot-piece is raised, the upper ends of the levers sliding in its grooves are forced farther apart and cause the jaws or lower ends ofthe levers to take a firm hold of `the bolt, and grip it with such force as to with- 

